Molding mechanism



Oct. 13, 1936;

l.. c. 'GUsTlN ET A;

MOLDING MECHANISM Originl Filed May 14, 1934 2 Sheets-Sheec 1 Zh /27 25h/' \f25 af@ @j L. C. GUSTIN ET AL MOLDING MECHANISM Original Filed May 14, 1934 2 Sheets-Sheet 2 www fzf

YPatented Oct. 13, 1935 than PATENT OFFICE 2,051,377 MoLmNG MECHANISM v Lester C. Gustn, Winchester, and Richard F.-

' Hoiiin,` Nortlrltandolph,A Mass., assignors tor Harold G. Starke, Arlington, Mass.; trustee Application May 14; 1934, serial No. 725,488 Y Renewed March 16, 19st` 20 Claims.

This invention relatesto molding mechanism and particularly to a two part mold adapted to be attached to af molding press and give a direct pressure to a moldingcoinposition, and subsequently vimpart a flowing pressure to the, particles of said composition, thereby attaining a greater adhesion of said particles to each other.

`'hejobject of `the invention is to produce by compression and rubbing or flowing .actionH a li) molded article having great strength and rigidity.

This objectis attained by the mechanism i1- lustrated in the accompanying drawings.

v For the purpose of Villustrating the'inventiom one preijerredform thereof is`il1ustrated` in the l5 drawings, this form having beenl found to give satisfactory and reliable results,` although it is to be understood `that the various instrumentali ties rci which the invention consists can be variously arranged and organized, and the invention is not limited to the precise arrangement and organization of these instrumentalities asv herein-shown and described except `as required by the scope of the appended claims. Of the drawings: Figure 1 represents an elevationof a mold embodying theprinciples of the present invention,`

he cover plate being cut away and the plunger being 'shown in loading position.

Figure 2 represents a similarelevation with the Y :j plunger in lowered position.

- Figure 3 represents a similar elevation of the ejector raised by a cam member and imposition to eject a molded article from the housing.

Y Figure 4 represents a vertical section on line e, l4 on Fig. l2. 4,

Figure 5 represents a horizontal 4section on line 5, 5 Von'Fig.` 4 Figure, 6 represents an elevation of a modication of said mold, the cover plate being cut O away. Y

Figure 'l represents a similar elevation with plunger and ejectorin position to mold'an article.

Figure 8 `represents a vertical section on line 3,'8Jon`Fig.` 7. *E Y,

Figure 9 represents a horizontal section on line 9, 9 on Fig. 6. f

Figure 10 represents vertical section of a modiiied form of `mold for forming cylinders,vand

Figure 11 representsV a section of same on line |I,IIon.F igf10. H Y

Similar characters indicate like parts throughout the several iigures of the drawings.

In the drawings,` ID is a portion of a frame havi1 ing a housing IIsec-ured thereto'byl bolts I2.

(Cl. 18-16) Y This housing `Il has a cover'IS secured thereto by bolts I4, A'

The cover I3 has secured Yto-its inner face a plate I5'Y by means of'screws `I6,`the upper inner face of said plateY I5 being inclined as shown at 5 I'Ylin'Fig; 4 of the drawings. f

Thisiinclined face may be flat as indicatedv in Fig. 5 of the drawings, or it may be shaped otherwise according'r to the article-tto be molded.

Disposed in the lower end ofthe housing I I is a 1U sli-dable ejector I8 having at itslowerend a roller i9 which is adapted to'coact with a cam member 20 movable beneath said roller andv forming a part of a molding machine.

The ejector I8 hasa depression l8r: in oneiaoe 1;, into whichjprojects the plate vI5 accurately filling said depression. l Y Y This molding machine may be of any well known construction and requires no illustration.

Above the housing and alined withfthe ejector I8 is a plunger 2| having at `its lower end a chambcred recess 22V shaped toform a shoe heel.

The plunger 2| is secured at 23to a vertically movablememberZll forming'a part of the molding press and tov which power may be applied in any well known manner to `move the plunger downwardly and compress the molding composition. A

In `the housing -II is a `loading cavity 25 in which is adapted to be disposed *a lump 26' of dough formed from a molding composition.

This composition is preferably composed of an inert iiller in a solution containing` a gummy adhesive, Celluloid and drying oil, although it may be formed from an inert filler in a solution 3 containing a gummy adhesive and celluloid, or an inert ller in a binding solution.

The ingredients of the composition are combined in lsuch proportions and in such a manner that adhesion between the particles thereof takes place by means of a direct pressure followed by a flowing or rubbing action.

By varying' the proportions of the ingredients and the manner of mixing the same, the consistency of the'molding composition can `be varied 45 from that of Warm tar to that of a moist powder.

This composition may be poured, shaken,

Y dropped, ejected under pressure, vor forced by mechanical means into the loading cavity 25 and this cavity its preferably one androne-half to `two times 50 the volume of the finished article lto be molded, thisvariation being according to the density of the molding composition used.

The molding cavity 22 in` the bottom ci' the plunger zllconforms-to the-shape of the finished 55 molded article and' may be formed in one piece or several pieces according to the shape of the article to be molded and the way it is to beejected from the mold.

The plunger 2| in the operation of the molding mechanism passes through the loading cavity 25, pushing or forcing the loading charge 26 of the molding composition ahead of it and forces this composition into the various curves and contours of the molding cavity 22.

The bottom of the plunger having the molding cavity 22 therein usually forms one face of the molded article and' its downward movement is adjusted so that its stroke nishes at the point where this upper face of the molded article is formed.

In the housing I I and at the bottom of the loading cavity 25 are laterally extending overflow openings 21.

These overflow openings 21 may be of various sizes and shapes depending on the consistency of the molding composition, the flowing pressure of the dough or powder, the power or amount of pressure exerted by the plunger, the speed at which the plunger V2| is operating, the amcuntvof excess material to be forced through the overflow openings 21 to obtain the desired' adhesion and the size and shape of the article to be molded.

The overflow may be through one or more openings 21, the essentialfeature being that the molding material must be forced through these overflow openings 21 under pressure-and that said overflow continue through these openings in an unbroken ribbon or flow 28 until the molding operation is completed and the pressure released or until the overflow opening is closed by mechanical means prior to the final completion of the molding stroke of the plunger 2|.

In Figs. 6, 7 and 8, the surplus material is ejected through the openings 21 prior to thevcompletion of the downward stroke of the plunger 2|, these openings then being closed by the plunger 2| and thek nal discharge of any remainingk material being through openings 29 which are located at points where the plunger 2| reaches the limit of its downward stroke.

In other words, the overflow openings 21 may remain open at all times during the molding operation as shown in Fig. 1, or these overflow openings 21 may be opened mechanically when the pressure of the molding composition has reached a certain point, or they may be open at the beginning of the molding process and closed mechanically just before the process is completed, as shown in Fig. 6.

These overflow openings 21 may also be opened mechanically when the pressure on the molding operation has reached a certainpoint and closed mechanically just before the process is completed'.

The one essential feature of the invention, how-4 ever, is that at some time during the actual molding process, the molding composition must be allowed to flow in unbroken streams or ribbons 28 through the overow openings 21 while under pressure created by the movement of the plunger 2|. l

This permits a compression of the molding materia] by direct pressure and then a rubbing or flowing action which will cause the particles of the composition to flow in different directions in the molding cavity 22 rubbing against each other and thus producing an adherence between the particles which give the finished article a greater rigidity and strength.

The ejector I8, which 'is movable, is adapted' tobe moved upwardly by the cam member 20 when the molded article is to be ejected from the mold. The upper surface of this ejector I8 forms a lower face or a portion of the lower face of the molding cavity 22 opposite the upper face of the molding cavity 22 formed by the plunger 2 I.

During the molding of the article, the ejector I8 is inr position to form the lower part of the face of the molding cavity 22 except in such cases where it is desired to have the molding composition subjected to a pressure higher than the pressure of flow, in which case the ejector is raised or forced forward so it may act as a valve to cover the overflow openings 21 and held in that position by a pressure equal to that by which the molding composition is to be subjected before it is allowed to flow.

When this pressure is reached during the molding operation, the pressure forces the ejector I8 tc-its extreme lower position, thus uncovering the overflow openings 21 and allowing the rubbing action of the molding composition to take place.

When the molding has been completed the ejector I8 is raised-and the molded article lifted from the molding cavity 22 up through and beyond the loading cavity 25 to a point from which it may be removed from the housing II.

'I'he housing II, which acts as a support for the moving parts 2| I8 and encloses the same, is attached to the support I0 of the machine proper when the molding is being done by machine.

In Figs. 1 to 5 a mold is shown adapted for molding an unfinished heel block, while in Figs. 6 to 9 inclusiveris shown a mold adapted t0 mold a finished heel, members 30 and 3| being inserts secured respectively in the plunger 2| and the ejector I8.

The member 30 extends below the lower end of the plunger 2| and the member 3| extends above the upper end of the ejector I8, thereby leaving a space 39a: between the plunger 2| and the ejector I8, as shown in Figs. 6 and '1 of the drawings.

These members 30, 3| may have their inner faces so shaped as to produce during the molding operation any desired shape of heel or other article.

By providing the members 30, 3| the size and shapes of the molded articles may be varied without making it necessary to have an individual mold for every size and shape of molded article. At the start of the molding operation in the modification shown in Figs. 6 to 9 inclusive, the top of the ejector I8 is at a point above the position shown in these gures, thereby closing the overflow openings 21.

When the pressure in the molding cavity 25 caused by the downward movement of the plunger 2|. reaches a standstill, the ejector I8 is forced downwardly so as to uncover the overflow openings 21 and allow the molding composition to flow therethrough.

By such a construction the overflow openings 21 are opened mechanically at a given pressure after the molding operation has started.

In Figs. l0 and 1l, a mold 32 is shown adapted for molding cylinders.

In this case a loading cavity 33 and the molding 'cavity 34 are continuous with the overflow opening 35 located in the lowest part of the molding cavity 34 which is circular in shape.

The overflow opening is in a removable disk 35 which may be replaced by another disk having a larger orsmaller overflow opening 35 therein.

The plunger 2| in this case has a dowel 31 se- CIV fantasie;r

cured,` to i the lower end thereof having an tapered lower endwhich lits into the overilowopening; 3,5 and closesrthe same when theA plunger is in its lowestrpositiom thus acting as a valve to shut ofi the,y overflow. ,.v t

.l The dowel; 31 may begunscrewed lfrom the plunger 2| and another dowel substituted therefor havingA a diiferentfdiameter.

By this construction cylinders having bores of variousldiametersmay be molded which will have great; strength and rigidity. -llavingthus described our invention, we claim: 1. A `mold for molding` plastic compositions comprising; au housing having ,molding and loading cavities therein, and a plunger by which the composition is rsubjected to direct pressure, said housing .having `horizontal slitsv` forming outlet or overflow.l ,openings through which vsome of-` `the composition is ejected under an-dprior .to thecompietion `of, pressure duringthe molding operation. `2, A mold, for molding plastic compositions comprising ahousing having molding and loading cavities ,.therein, and av plunger by which the comition Ais subjected to direct pressure, said housing having horizontal slits forming outlet or overflow openings through which some oi the composition is 'ejected' under pressure during vone partici 'the moldingoperation and prior to the completion `of s'aidoperation, said housing having other `overovv openings uncovered at the completion of the kdownward movementV of said plungeni?H i L 1 mold forli` molding plastic compositions comprising a housing having molding and 'loading cavities therein, and a plunger by which thev composition is subjected todirect pressure, said housing having two sets of lateral outlet or overflow openings in the walls thereof through one set of which some of the composition is ejected under pressure during the molding operation and through the other set of which surplus material may be ejected at the end of the downward stroke of said plunger. i

4. A mold for molding plastic compositions comprising a housing having molding and loading cavities therein, and a plunger by which the composition is subjected to direct pressure, said housing having outlet or overflow openings through which a limited amount of the composition is ejected under pressure during and prior to the completion of the molding operation thereby causing adhesion to take place by the particles of the composition remaining in the molding cavity to rubbing or flowing against one another.`

5. A mold for molding plastic compositions comprising a housing having molding and loading cavities therein, and a plunger by which the composition is subjected to direct pressure while the end of said plunger is diminishing the volume of said molding cavity, said housing having outlet or overilow openings above the bottom of the molding cavity through which some of the composition is ejected under pressure during and prior to the completion of the molding operation. 6. A mold for molding plastic compositions 'comprising al housing having molding and loading cavities therein, a plunger by which the composition is vsubjected to direct pressure, said housing having lateral outlet or overiiow openings above the bottom of themolding cavity through which some of the composition is ejected under pressure during and prior to the completion of the molding operation, an ejector by which the molded article is ejected from said housing and having a depression in one Vface thereof; and a Xedplate'extending into said depression with its upper end conforming to one face ofi the article vbeing molded. i

L'lz., A mold for molding a plastic composition comprisingya housing having a molding cavity therein, 1 a` reciprocable plunger the endA of kwhich forms one face of said molding. cavity, said housinglhaving lateral overflow openings in the side wallsfthereof through which limited quantities of the molding composition are ejected while .subjected to direct' pressure from said plunger;

andrmeans for vclosing, said openings prior to the completion .of the. Vdownward stroke of said plunger.

8. A mold for molding a vplastic composition comprising a housing having a molding -cavity therein; and a reciprocable plunger the end of which forms ,oneV face of said molding cavity, said housing` having lateral overowopenings through which limited quantities of the molding composition are ejected while `subjected to direct pressure from said plunger and said plunger acting dur-ing some part of the molding operation as a valve to close the overowopenings before the molding `operation `is completed.

" 9. A mold for molding a plastic Vcomposition Y comprising a housing having `a molding cavity therein and provided with overflow openings therefrom, a valve in the molding cavityadapted to close said overflow openings and remain closed until direct pressure on the molding composition reaches a given point and then toV move to uncover vsaid overow openings.

10. A mold for molding a plastic composition comprising a housing having a molding cavity therein and provided with overflow openings, and a reciprocable plunger in said molding cavity to give a direct pressure to the composition, said overflow openings being located opposite a. side face of the article being molded and above the bottom of the molding cavity.

11. A mold for molding a plastic composition comprisingV a housing provided with a molding 'cavity and having an overflow opening in the bottom thereof, a plunger for imparting pressure to the composition in said molding cavity, and a removable dowel extending downwardly from said plunger adapted to form an opening in the article being molded, the lower end of said dowel acting as a. valve to close the overow opening from said molding cavity at the completion of the molding operation.

12. A mold for molding a plastic composition Y comprising a housing having a molding cavity therein and provided with overflow openings, and` a reciprocable plunger in said molding cavity to give a direct pressure to the composition; `and means movable with and forming a part of said plunger for closing said overflow openings for a limited period, then uncovering said openings when the pressure on the 'composition has reached a predetermined amount, and then again closing the openings prior to the completion of the downward movement of saidplunger.

13. A mold for molding a plastic composition comprising a housing having a molding cavity `and provided with lateral overflow openings therefrom at points above the bottom of the molding cavity, a reciprocable plunger in said molding cavity to give a direct pressure to the composition, a reciprocable ejector in said housing, and inserts in said ejector and plunger having oppositely disposed shaped faces for molding the composition, said inserts being adapted to be replaced by other inserts having diierently opposed shaped molding faces.

14. A mold for molding a plastic -composition comprising a housing having a molding cavity therein and provided in the bottom thereof with interchangeable inserts each having a`different sized overow opening leading from the molding cavity; and a plunger in said lhousing having a dowel adapted to close said opening atrthe end of the downward stroke of said plunger.

15. The method of molding a plastic composition in which an excessive amount of the cornposition is deposited in a molding cavity extending part way into a loading cavity, then subjecting the 'composition to direct pressure and compression until a certain pressure is reached, at which point a limited amount of the composition is allowed to escape from the molding cavity through an overiiow opening while still subjected to pressure, and then closing said overflow opening before the pressure on said composition has been completed.

16. A mold for molding plastic compositions comprising a housing having a molding cavity from which extendsranoverflow opening above the bottom of said cavity and a slidable member for uncovering said opening for a limited time at an intermediate point in the compression of said composition. Y

17. A mold for molding plastic compositions comprising a housing having a molding cavity from which extends an overflow opening above the bottom of said cavity and a slidable member for compressing the composition and uncovering said opening for a limited time at an intermediate point in the compression of said composition.

18. A mold for molding plastic compositions comprising a housing having a molding cavity from which'extends an overow opening above the bottom of said cavity, and a slidable compressing plunger closing said opening at one point in its movement.

19. A mold for molding plastic compositions comprising a housing having a molding cavity from which extends an overflow opening above the bottom of said cavity, and a slidable ejecting plunger closing said opening at one point in its movement.

20. The method of molding a composition selfadherent only under pressure accompanied by iiowing or rubbing action which comprises confining a batch of such composition in a mold, closing the' mold while leaving an escape port of an area very limited as compared with the area ofthe mold closure, and moving the mold closure under high pressure to compact the composition and cause owage thereof until a limited portion thereof has flowed under great pressure through said escape port, thereby redistributing under pressure with accompanying flowing or rubbing action the remaining compacted composition article.

LESTER C. GUS'I'IN. RICHARD F. HOFLIN.

into a dense strongly self-adherent 

